Generally fastening elements of the type shown are already known (German disclosure letter No. 24 06 231). It serves to fasten an article to a workpiece provided with an aperture, e.g. a sheet metal plate. The lamellar flexible ribs make possible an effective fastening of articles of different thicknesses to a holding element, in that dependent on the thickness of the article a corresponding lamellar rib grips beneath the edge of the aperture at the underside of the holding element, for instance, a sheet metal plate. The handling of such fastening elements is extremely simple, because they only have to be forced or beaten into an aperture via their head. For this reason the field of application of such fastening elements also is extraordinarily wide and many-sided.
The described known fastening element has proved to be extremely useful in practice. In the known fasteners, nevertheless, the danger exists sometimes that the lamellar ribs may be loaded too much and will break away because of their relatively short length (see U.S. Pat. No. 3,810,279) when the shank of the fastening element is not centrically introduced into the fastening aperture.